A new IAEA publication, Uses of Ionizing Radiation for Tangible Cultural Heritage Conservation, highlights the application of radiation technology for disinfection and restoration of cultural heritage objects and provides advice and tips to radiation technologist who intend to collaborate with art curators, restorers, historians and archaeologists on the use of this advanced technology.

Radiation technology can be used to restore and maintain artefacts for the benefit of future generations without causing any measurable damage, emphasized Sunil Sabharwal, an IAEA radiation processing specialist responsible for the publication.

Traditionally, chemical and physical methods were used for the treatment and restoration of artefacts, but these have drawbacks and limitations, Sabharwal said. Chemical methods can leave undesirable substances in or on the objects, possibly causing harm later to the restorers or the environment, while physical methods can harm the object itself.

By contrast, radiation treatment does not leave any trace on the treated object or causes any damage. It also does not make the artefact radioactive.

The publication provides a comprehensive introduction of radiation processing technology for the restoration and preservation of cultural heritage, including an overview of the most commonly-used radiation techniques, the effects they have on the materials, as well as the experience of cultural preservation using radiation technology in several countries, including Brazil, Croatia, France, Romania and Tunisia.

One of the methods it describes is gamma-ray panoramic irradiation, which is a frequently used sterilization technique to destroy insect and microbial contaminants. It uses a radioactive source to induce chemical changes in the DNA of these organisms and inactivate them, without incurring any physical or chemical changes in the objects themselves.

First of its kind

The radiation treatment of cultural artefacts normally consists of three parts:

Characterisation, which is the process of examining and identifying the various properties of a tangible cultural heritage artefact, such as its origin, age and the materials it is made of;

Consolidation, which is the process of applying deeply penetrating materials to re-establish the bond between particles of deteriorated objects; and

Preservation: “The use of radiation technology for characterisation has been around for decades and it is a familiar subject for many,” Sabharwal said. But there has been no comprehensive document on the use of radiation technology for consolidation and preservation, he said. “This publication is intended to fill that knowledge gap.”

The publication could help dispel some of the myth surrounding the use of radiation technology in cultural heritage preservation, he said. “Many people are afraid of radiation, even more so for those working in the area of art preservations,” Sabharwal said. “In order to convince them to give radiation technology a try, having a comprehensive and official publication with success stories, showing that this is a proven method with continuous applications is important.”